It is known to use discharge plasma produced sources to generate extreme ultra-violet (EUV) light for use in lithography systems. Reticle inspection system light source requirements are different than source requirements for lithography systems. As a result, for technical and economic cost reasons, typical EUV light sources for lithography systems do not meet the inspection light source requirements for reticle inspection systems. From a technical point, the brightness of EUV lithography discharge plasma produced sources do not have the brightness or size required for reticle inspection systems. Also, the repetition rates for individual discharge plasma produced sources are too low for use in reticle inspection systems.
It also is known to use a single discharge plasma produced source per light source system. Therefore, to increase EUV light output, it is necessary to install multiple light source systems, increasing the overall footprint of a system in which the multiple light sources are installed.